CN116130121A - Fused salt reactor based on heat conduction of heat pipe - Google Patents

Abstract

The invention discloses a molten salt reactor based on heat conduction of a heat pipe, which comprises a main container, an annular cylinder, the heat pipe and at least one graphite matrix, wherein a cavity for flowing fuel molten salt fluid is arranged in the main container, the annular cylinder is soaked in the fuel molten salt fluid to define a first flow space and a second flow space from the cavity, the hot end of the heat pipe is arranged in the first flow space, the at least one graphite matrix is arranged in the second flow space, the second flow space is used as a heat source, and the first flow space is used as a cold trap, so that natural circulation flow of the fuel molten salt fluid is formed between the first flow space and the second flow space. The fused salt reactor based on heat conduction of the heat pipe adopts the heat pipe to conduct heat of the main container, and forms an integrated reactor, all coolants in contact with the core fuel are always contained in the main container, so that accident consequences caused by breakage of a large flow pipeline are avoided, and the heat exchange coefficient of natural circulation flow heat exchange is high.

Description

Fused salt reactor based on heat conduction of heat pipe

Technical Field

The invention relates to the field of nuclear power plant system equipment and safety, in particular to a fused salt reactor based on heat conduction of a heat pipe.

Background

Molten salt reactor is a kind of nuclear fission reactor, its main coolant is a mixed salt in molten state, typically LiF, beF2, in which the sub-reaction section is small and can be well eutectic with fuel.

The core is free of fuel assemblies, and fuel is mixed with molten salt fluid as reactor media and heat transfer media that can flow continuously between the core and the external heat exchanger. When molten fuel salt is in the reactor core, the molten fuel salt can be cracked to generate heat due to the slowing; heat is transferred to the heat exchanger while flowing through the external heat exchanger. The boiling point of the molten fluoride salt is about 1400 c, well above the reactor operating temperature, and the medium does not boil at atmospheric pressure, which reduces the pressure experienced by the pressure vessel and piping.

The fuel outlet and inlet temperatures of a typical molten salt reactor system are 700 ℃ and 500 ℃, respectively, and the outlet temperature can also be increased to 800 ℃ to increase the thermal efficiency of the reactor. The molten salt reactor works at a higher temperature, so that the brayton cycle generator with higher thermal efficiency can be driven, and the thermal efficiency of the whole reactor is improved.

In the existing molten salt reactor system, the fuel salt is LiF-BeF2-ZrF4-UF4 during operation, wherein uranium tetrafluoride is adopted as fuel, and when the fuel is used, the fuel is firstly pretreated to form additive salt (LiF-UF 4), and then the additive salt is dissolved in the base salt. During the life of the reactor, the fuel salt is always in operation in the reactor and is not treated and recovered. The loading and unloading of the fuel salt is carried out by the gas pressure difference between the reactor core and the fuel salt discharge tank.

The core, the main pump, and the molten salt/molten salt heat exchanger are located within the reactor vessel, and heat is generated as the fuel salt flows through the core. Under normal operation, the primary circuit fuel salt is driven by the circulating pump, the fission energy is transferred from the primary circuit to the secondary circuit through the fused salt/fused salt heat exchanger, then the secondary circuit cooling salt is driven by the circulating pump, and the heat is discharged into the air environment through the fused salt/air heat exchanger. Under the condition of normal stack shutdown, waste heat is finally released into the atmosphere through a loop system; under the accident condition that the loop works normally, waste heat is finally released into the atmosphere through the loop system; under the accident condition that the loop can not work normally, the passive waste heat discharging system is utilized for waste heat discharging.

The reactor body system comprises a main vessel, a graphite core, a flow distribution device, a control rod system, a molten salt/molten salt heat exchanger of a related functional channel and a fuel salt loop system, and a fuel salt circulating pump. The reactor body is used for accommodating the whole primary loop, containing fuel salt, and is responsible for effectively transferring the fission energy generated by the liquid fuel to the two-loop thermodynamic system through the forced circulation and the heat exchanger during normal operation of the reactor, and effectively transferring the reactor waste heat to an environmental heat trap through the passive waste heat discharging system under the shutdown state. The pile body system has a complex structure and adopts more movable parts.

Disclosure of Invention

The invention aims to solve the technical problem of providing a molten salt reactor based on heat conduction of a heat pipe.

The technical scheme adopted for solving the technical problems is as follows: a molten salt reactor based on heat pipe conduction is constructed, comprising: a main container, an annular cylinder, a heat pipe, and at least one graphite substrate;

a cavity for flowing fuel molten salt fluid is arranged in the main container;

the annular cylinder is of a cylindrical structure with two open ends, the annular cylinder is soaked in the fuel molten salt fluid to define a first flow space and a second flow space by the cavity, the hot end of the heat pipe is arranged in the first flow space, and the cold end of the heat pipe extends out of the main container so as to lead out the heat of the reactor from the main container;

at least one graphite substrate is arranged in the second flow space, a plurality of coolant flow channels which are distributed at intervals are arranged in each graphite substrate, and the coolant flow channels penetrate through the two opposite end surfaces of the graphite substrate and are communicated with the first flow space;

the graphite matrix is used as a moderator, nuclear reaction occurs on nuclear fuel in the fuel molten salt fluid in the second flow space, so that heat is generated, the second flow space is used as a heat source, and the first flow space is used as a cold trap, so that natural circulation flow is formed between the first flow space and the second flow space by the fuel molten salt fluid.

In some embodiments, the heat pipe comprises a plurality of heat pipe units which are arranged at intervals, and each heat pipe unit comprises an outer wall body, a liquid suction core for flowing liquid medium and a steam flow channel for flowing metal steam, wherein the outer wall body, the liquid suction core and the steam flow channel are sequentially arranged from outside to inside along the circumferential direction.

In some embodiments, each of the heat pipe units further comprises a heating evaporation section immersed in the molten fuel salt fluid and a heat dissipation condensation section extending out of the main container, and each of the heat pipe units has a capillary force;

the liquid medium absorbs heat in the heating evaporation section to evaporate so as to form the metal vapor to flow in the vapor flow channel, the metal vapor is condensed in the heat dissipation condensation section to form the liquid medium, and then the liquid medium flows back to the heating evaporation section through the liquid suction core so as to form a heat transfer circulation loop inside the heat pipe.

In some embodiments, the heat pipe unit further comprises a heat pipe insulation section disposed between the heating evaporation section and the heat dissipation condensation section.

In some embodiments, the thermoelectric conversion system further comprises a thermal insulation flow channel;

the heat-preserving flow passage is arranged outside the main container, and the heat pipe unit extends out of the main container, enters the heat-preserving flow passage after passing through a heat-pipe heat-preserving section and is connected with the thermoelectric conversion system after passing through a heat-pipe heat-preserving section.

In some embodiments, the heat-preserving flow channel is a closed chamber, all the heat pipe units pass through the heat-preserving flow channel, an air inlet pipeline and an air outlet pipeline are connected to the heat-preserving flow channel, a first control valve is arranged on the air inlet pipeline, and a second control valve is arranged on the air outlet pipeline.

In some embodiments, an insulation layer is arranged on the outer wall surface of the insulation flow channel, and the insulation layer is made of an insulation material.

In some embodiments, the reactor further comprises a reflecting layer attached to the inner wall surface of the annular cylinder for reflecting neutrons into the reactor core.

In some embodiments, the annular cylinder is a cylindrical structure made of carbon composite or hastelloy.

In some embodiments, a vacuum layer is provided in the annular cylinder wall for avoiding heat transfer from the first flow space and the second flow space to enhance natural circulation.

In some embodiments, a control rod assembly is also included, the control rod assembly including a reactive control rod and a shutdown rod;

and a plurality of control pore canals for inserting the reactive control rods and shutdown pore canals for inserting the shutdown rods are arranged in the graphite matrix.

In some embodiments, the fuel molten salt fluid upper portion is covered with an inert gas.

The implementation of the invention has the following beneficial effects: the molten salt reactor based on heat pipe conduction comprises a main container, an annular cylinder, a heat pipe and at least one graphite matrix, wherein a cavity for fuel molten salt fluid to flow is arranged in the main container, the annular cylinder is of a cylindrical structure with two open ends, the annular cylinder is soaked in the fuel molten salt fluid to define a first flow space and a second flow space, the hot end of the heat pipe is arranged in the first flow space, the cold end of the heat pipe extends out of the main container to lead out heat of the reactor from the main container, the at least one graphite matrix is arranged in the second flow space, a plurality of coolant flow channels which are distributed at intervals are arranged in each graphite matrix, the coolant flow channels penetrate through two opposite end faces of the graphite matrix and are communicated with the first flow space, the graphite matrix is used as a moderator, nuclear reaction occurs in the fuel molten salt fluid in the second flow space, so that heat is generated, the second flow space is used as a heat source, and the first flow space is used as a cold trap, so that the fuel molten salt fluid forms natural circulation flow between the first flow space and the second flow space. The fused salt reactor based on heat conduction of the heat pipe is used for conducting heat of a reactor core, the heat pipe generates capillary driving force by itself and is passive equipment, the heat pipe is directly inserted into the main container to form an integrated reactor, a large-size flow pipeline is avoided, all the coolant directly contacted with the reactor core fuel is always contained in the main container, the accident consequence caused by breakage of the large flow pipeline is avoided, and the natural circulation flow heat exchange is higher than the heat exchange coefficient of the pool type heat exchange.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the following description will be given with reference to the accompanying drawings and examples, it being understood that the following drawings only illustrate some examples of the present invention and should not be construed as limiting the scope, and that other related drawings can be obtained from these drawings by those skilled in the art without the inventive effort. In the accompanying drawings:

FIG. 1 is a schematic diagram of a molten salt reactor based on heat pipe conduction in some embodiments of the invention;

FIG. 2 is an enlarged schematic view of a structural part of a molten salt reactor based on heat pipe conduction in some embodiments of the invention;

FIG. 3 is a structural top view of a molten salt reactor based on heat pipe conduction in some embodiments of the invention;

FIG. 4 is a structural elevation view of a heat pipe in some embodiments of the present invention;

FIG. 5 is a structural top view of a heat pipe in some embodiments of the present invention.

Detailed Description

For a clearer understanding of technical features, objects and effects of the present invention, a detailed description of embodiments of the present invention will be made with reference to the accompanying drawings. In the following description, it should be understood that the directions or positional relationships indicated by "front", "rear", "upper", "lower", "left", "right", "longitudinal", "transverse", "vertical", "horizontal", "top", "bottom", "inner", "outer", "head", "tail", etc. are configured and operated in specific directions based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present invention, and do not indicate that the apparatus or element to be referred to must have specific directions, and thus should not be construed as limiting the present invention.

It should also be noted that unless explicitly stated or limited otherwise, terms such as "mounted," "connected," "secured," "disposed," and the like are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. When an element is referred to as being "on" or "under" another element, it can be "directly" or "indirectly" on the other element or one or more intervening elements may also be present. The terms "first," "second," "third," and the like are used merely for convenience in describing the present invention and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated, whereby features defining "first," "second," "third," etc. may explicitly or implicitly include one or more such features. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

Referring to fig. 1 to 5, a molten salt reactor based on heat conduction of a heat pipe in some embodiments of the present invention can be used for generating electric power of 1 MWe-50 MWe, and has the characteristics of simple structure, full passive, high integration, high safety, and the like, and has certain advantages for building movable distributed energy sources and special scene power supply. The molten salt reactor based on heat pipe conduction comprises a main container 1, a heat pipe 3, an annular cylinder 2 and at least one graphite substrate 4, wherein a cavity 11 for fuel molten salt fluid 14 to flow is arranged in the main container 1 and is used as a boundary of a reactor loop to contain the whole reactor loop. The main container 1 is a cylindrical structure made of stainless steel, which has good strength and rigidity, is resistant to corrosion, high-temperature oxidation and simple to maintain, and the cross section of the main container 1 may be circular or hexagonal, and in other embodiments, the cross section of the main container 1 may be rectangular, elliptical or other shapes, which are not particularly limited herein.

Specifically, the annular cylinder 2 is a cylindrical structure with two open ends, and is immersed in a molten fuel salt fluid 14 to define a first flow space 12 and a second flow space 13 in the chamber 11, the hot end of the heat pipe 3 is disposed in the first flow space 12, the cold end of the heat pipe extends out of the main container 1 to guide heat of the reactor out of the main container 1, the at least one graphite matrix 4 is disposed in the second flow space 13, a plurality of coolant channels 41 are disposed in each graphite matrix 4 at intervals, the coolant channels 41 are generally circular in cross section, the coolant channels 41 penetrate through opposite end surfaces of the graphite matrix 4 and are communicated with the first flow space 12, nuclear reaction occurs in the fuel molten fuel in the second flow space 13, thereby generating heat, namely, the second flow space 13 serves as a heat source, and the first flow space 12 serves as a cold trap, so that the molten fuel salt fluid 14 forms natural circulation flow between the first flow space 12 and the second flow space 13. The coolant flow channels 41 are sized and dimensioned according to the reactor requirements and design.

The annular cylinder 2 is used for separating the graphite matrix 4 and the first flow space 12 of the heat-containing tube 3, and is used for supporting and fixing the graphite matrix 4, and it is understood that in the natural circulation, the graphite matrix 4 serves as a moderator, nuclear reaction occurs on nuclear fuel in the fuel molten salt fluid 14 in the second flow space 13, so that heat is generated, the first flow space 12 of the heat-containing tube 3 serves as a cold trap, and the fuel molten salt fluid 14 flows in the graphite matrix 4 from top to bottom, so that flow heat exchange is performed on the outer wall surface of the heat tube 3. The first flow space 12 is annular and the second flow space 13 is circular.

It will be appreciated that natural circulation is a passive technique whose basic principle is to drive the flow of the molten fuel salt fluid 14 using the driving force generated by the density difference. When the fuel molten salt fluid 14 is heated in the graphite matrix 4, the density of the fuel molten salt fluid 14 is reduced due to thermal expansion and contraction, at this time, the fuel molten salt fluid 14 in the upper cavity of the reactor is not heated, so that the density is relatively high, natural circulation driving force is generated under the action of density difference, the fuel molten salt fluid 14 flows upwards under the action of the driving force, heat generated by the core is carried into the upper cavity, heat exchange is carried out through the heat pipe 3, and the fuel molten salt fluid 14 in the first flow space 12 is required to supplement the fuel molten salt fluid 14 in the second flow space 13, so that natural circulation is formed in the main container 1.

Wherein for smaller reactor designs, the entire core can be designed as an entire graphite matrix 4; for larger reactor designs, the entire core may be designed as a plurality of graphite matrices 4 assembled. The graphite material has high temperature resistance and excellent molten salt corrosion resistance. The advantages of using a graphite matrix 4 are: the graphite has high heat conductivity coefficient, can effectively conduct heat of different coolant channels, is convenient for homogenizing heat of a reactor core, and is a good neutron moderating material.

In some embodiments, the heat pipe 3 includes a plurality of heat pipe units 31 disposed at spaced intervals, as shown in fig. 4 and 5, each heat pipe unit 31 includes an outer wall body 311, a wick 312 through which a liquid medium flows, and a steam flow channel 313 through which metal steam flows, which are sequentially disposed from outside to inside in a circumferential direction. And each heat pipe unit 31 further includes a heating evaporation section 314 immersed in the molten fuel salt fluid 14 and a heat dissipation condensation section 315 protruding outside the main container 1, and each heat pipe unit 31 has capillary force, the liquid medium absorbs heat in the heating evaporation section 314 to evaporate, thereby forming metal vapor flowing in the vapor flow channel 313, the metal vapor is condensed in the heat dissipation condensation section 315 to form a liquid medium, and then flows back to the heating evaporation section 314 through the wick 312 under the action of the capillary force, thereby forming a heat transfer circulation loop inside the heat pipe 3. The heat pipe 3 is fixed and sealed at the upper cover surface of the main container 1.

It can be understood that the heat pipe 3 is in a circular tube shape, two ends of the heat pipe are sealed, each heat pipe unit 31 is a single sealed unit, and the outer wall 311 of the heat pipe 3 is preferably made of stainless steel, so that the heat pipe 3 has good strength and rigidity and is not easy to break. The wick 312 of the heat pipe 3 is filled with a liquid medium, the liquid medium is vaporized by absorbing heat through the heating evaporation section 314, the metal vapor flows to the heat dissipation condensation section 315 in the vapor flow channel 313 to release heat and condense into the liquid medium, the liquid medium flows back to the heating evaporation section 314 under the action of capillary force of the heat pipe 3, the heat is circularly and repeatedly conducted from the heating evaporation section 314 to the heat dissipation condensation section 315, and the heat transfer efficiency of the fused salt reactor based on heat conduction of the heat pipe is realized through phase change of the working medium. Preferably, the working medium is preferably sodium metal or potassium metal.

The heat pipe 3 is driven by passive capillary force, does not need active equipment or gravity, and has the advantages of high heat conductivity, excellent isothermicity, long-distance transmission and the like by relying on the phase change of working liquid in the heat pipe to realize heat transfer. In addition, the heat pipe 3 has light weight and no moving parts, so maintenance is basically not needed, and the environmental adaptability is good.

It is worth mentioning that capillary action is the attraction of a liquid surface to a solid surface. The capillary tube is inserted into the infiltration liquid, the liquid level in the tube rises and is higher than the outside of the tube, the capillary tube is inserted into the non-infiltration liquid, the liquid in the tube descends and is lower than the phenomenon outside the tube. Capillary forces are induced by the meniscus within the three phase interface, with the direction of capillary force acting always toward the concave surface of the meniscus (concave convex meniscus refers to the side opposite the liquid phase). Capillary phenomenon occurs in capillaries where the capillary becomes curved across the surface of the liquid and the interactions between the liquid and solid molecules can spread across the liquid, with some degree of linearity being small enough to be compared to the radius of curvature of the liquid meniscus. The capillary force is proportional to the curvature of the meniscus, and the smaller the diameter of a capillary tube is, the larger the capillary force is; and vice versa. The greater the capillary force, the greater the capillary rise.

In some embodiments, the heat pipe unit 31 further includes a heat pipe insulation section 316 disposed between the heating evaporation section 314 and the heat dissipation condensation section 315, where the heat pipe insulation section 316 may be formed by coating an outer surface of a pipe with an insulation material. It will be appreciated that the heat pipe insulation section 316 functions to separate the heating evaporation section 314 and the heat dissipation condensation section 315 apart from providing a passage for fluid, and to prevent heat transfer between the working fluid in the pipe and the outside, and the heat pipe insulation section 316 may be disposed between the heating evaporation section 314 and the heat dissipation condensation section 315 according to application requirements.

Further, the molten salt reactor based on heat conduction of the heat pipe further comprises a heat preservation flow channel 5 and a thermoelectric conversion system 6, wherein the heat preservation flow channel 5 is arranged outside the main container 1, the heat pipe unit 31 extends out of the main container 1, then enters the heat preservation flow channel 5 after passing through a heat pipe heat preservation section 316, then is connected with the thermoelectric conversion system 6 after passing through a heat pipe heat preservation section 316, one section of the heat pipe unit 31 is an uninsulated section, heat is preserved through the heat preservation flow channel 5, and the heat preservation flow channel 5 is completely closed when the reactor normally operates. The thermoelectric conversion system 6 is used to absorb heat of the heat dissipation condensation section 315 and convert the heat into electric energy. The thermoelectric conversion system 6 may employ Stirling engine, thermocouple, brayton cycle, etc. techniques. Wherein, due to the principle and characteristics of the heat pipe 3, after the heat pipe 3 exits the main container 1, the arrangement trend of the heat pipe has little influence on the flow of the fuel molten salt fluid 14 in the pipe.

Preferably, the heat preservation flow channel 5 is a closed chamber, all the heat pipe units 31 pass through the heat preservation flow channel 5, the heat pipe units 31 do not preserve heat, the heat preservation flow channel 5 is connected with an air inlet pipeline 51 and an air outlet pipeline 52, the air inlet pipeline 51 is provided with a first control valve 511, and the air outlet pipeline 52 is provided with a second control valve 521. It can be understood that when the reactor is operating normally, the first control valve 511 and the second control valve 521 are both closed, wherein the heat insulation layer is disposed on the outer wall surface of the heat insulation flow channel 5, and the air inside the heat insulation flow channel is closed and static, which is equivalent to forming a large thermal resistance for the non-heat insulation section of the heat pipe, so as to avoid the heat loss in the heat pipe 3 to the environment; when an accident occurs in the reactor (for example, the thermoelectric conversion system 6 is damaged and cannot effectively absorb the heat of the heat dissipation condensation section 315), the inlet and outlet of the heat preservation flow channel 5 are opened to allow air to enter and exit, and the air flows through the outer wall surface of the superheat tube 3, so that the heat tube 3 is cooled, that is, the heat tube 3 transfers the heat to the air. The first control valve 511 and the second control valve 521 may be electric valves, and the electric valves receive signals from the control system, so as to open or close the inlet and outlet channels.

Further, the heat-insulating layer is made of heat-insulating materials. It will be appreciated that the insulating layer may provide the insulating flow channel 5 with a good insulating performance, resulting in no heat dissipation of the heat pipe 3 in this region, and that after the heat pipe 3 extends out of the main container 1, the heat pipe 3 will be insulated one by the insulating layer in the environment and without entering the part of the insulating flow channel 5. Preferably, the insulating material may be, but is not limited to, glass wool tubing, rock wool tubing, or polyurethane.

In some embodiments, the molten salt reactor based on heat pipe conduction further comprises a reflective layer 7. The reflecting layer 7 is attached to the inner wall surface of the annular cylinder 2 and used for reflecting neutrons to enter the reactor core so as to improve the neutron utilization efficiency of the reactor.

The annular cylinder 2 is a cylindrical structure made of carbon composite material or hastelloy. The carbon composite material or hastelloy can resist high temperature and molten salt corrosion, has better structural strength than graphite, and can be used as a structural material for supporting and fixing.

Preferably, a vacuum layer is provided in the wall of the annular cylinder 2. The vacuum layer is used for increasing heat transfer resistance, avoiding heat transfer of the first flow space 12 and the second flow space 13, and increasing temperature difference between the heat source and the cold trap to enhance natural circulation, thereby facilitating formation of natural circulation, and facilitating flow and heat transfer of the reactor core and the heat pipe 3.

Further, the molten salt reactor based on heat pipe conduction further comprises a control rod assembly 8, the control rod assembly 8 comprises a reactivity control rod 81 and a shutdown rod 82, and a plurality of control holes 42 for inserting the reactivity control rod 81 and shutdown holes 43 for inserting the shutdown rod 82 are formed in the graphite substrate 4. It will be appreciated that the reactivity control rods 81 may control the rate of reaction of the core reaction and the shutdown rods 82 may control the start-up and shut-down of the core reaction.

Preferably, the fuel molten salt stream 14 is capped on top with inert gas 16. It will be appreciated that in the upper small part of the space within the main vessel 1, an inert gas 16 is covered, which inert gas 16 may be helium, and the lower large part of the space is filled with a fuel molten salt fluid 14. The molten fuel salt fluid 14 may expand with heat and contract with cold, and the inert gas 16 may accommodate the change in volume of the molten fuel salt fluid 14.

Specifically, under normal operation of the reactor, the path of heat transfer is: the molten fuel salt fluid 14 of the second flow space 13-the first flow space 12-the heating evaporation section 314-the heat dissipation condensation section 315-the thermoelectric conversion system 6. The working fluid flow in the heat pipe 3 is natural flow by capillary force, so that no extra driving force such as a pump is needed for the flow of the whole system.

Under the condition that the reactor is in accident operation, for the accident that part of the heat pipes 3 fail, the redundancy of the heat pipes 3 is considered in the design of the reactor, a certain proportion of the heat pipes 3 are considered as redundancy, and the remaining intact heat pipes 3 can still discharge the core waste heat, so that the failure of part of the heat pipes 3 does not cause the over-temperature of the reactor; and each heat pipe 3 is completely independent, so that the probability of simultaneous failure of a plurality of heat pipes 3 is low. In addition, the specific heat capacity of molten salt in the reactor is high, and the molten salt can absorb redundant heat generated by the reactor core in a certain event by means of temperature rise of the molten salt.

For the accident that the normal cold source fails, for example, the thermoelectric conversion system 6 can not effectively absorb the heat of the heat dissipation condensation section 315, after receiving the reactor core overtemperature signal, the instrumentation and control system triggers the shutdown rod 82 to emergently shutdown the reactor, meanwhile, the inlet and outlet of the heat preservation runner 5 are opened, the air is introduced to cool the heat dissipation condensation section 315, the heat of the heat pipe 3 is not preserved, and the heat of the heat pipe 3 can be transferred to the air contacting the outer surface of the heat pipe 3, because the reactor is shutdown, the reactor core only generates decay heat, the heat removal requirement is far smaller than that before shutdown, and therefore the heat removal capability of natural ventilation is sufficient.

As can be appreciated, the molten salt reactor based on heat conduction by the heat pipe has the following beneficial effects compared with the prior art:

1. in the prior art, a main pump is used for driving molten salt fluid containing fuel, and a power supply is needed for the pump; the invention adopts the heat pipe 3 for conducting heat of the reactor core, the heat pipe 3 generates capillary driving force, and the heat pipe 3 is passive equipment, and can realize fluid flow in the heat pipe 3 without power supply.

2. The prior art has complex equipment and structure and distributed arrangement, and needs to adopt a main pump, a main heat exchanger, a main cooling flow pipeline and the like; the invention eliminates the devices, the heat pipe 3 is directly inserted into the reactor core to form an integrated reactor, the adoption of large-size flow pipelines for the coolant is avoided, and all the coolant which is in direct contact with the fuel of the reactor core is always contained in the main container 1, namely, no large flow pipeline exists outside the main container 1, so that the accident consequence caused by the breakage of the large flow pipeline is avoided.

3. In the prior art, once a main pump fails or a main coolant pipeline breaks, serious accident influence is caused to the whole reactor; in the present invention, the main pump is effectively decomposed into capillary driving force in hundreds of heat pipes 3, and the main coolant pipe is effectively decomposed into flow in hundreds of heat pipes 3, and the number of the heat pipes 3 has a certain redundancy with respect to the heat transfer requirement of the core, so that even if a certain number of the heat pipes 3 are broken and do not have heat transfer capability, the remaining heat pipes 3 still have sufficient heat transfer capability. All the heat pipes 3 are independent from each other, and the failure of one or a plurality of heat pipes 3 can not cause serious accident influence on the reactor.

For the breakage of the heat pipes 3, because one end is located inside the main container 1 and one end is located outside the main container 1, if only single-ended breakage is used, the coolant content of each heat pipe 3 is very small, and the single-ended breakage of the heat pipe 3 will not cause the external leakage of the molten salt fluid 14 in the main container 1, and the probability of the simultaneous breakage of the two ends is much lower than that of the single-ended leakage; in the reactor of the present invention, the primary circuit pressure is normal pressure, no pressure difference exists with respect to the external environment pressure, and the portion of the heat pipe 3 located in the environment is located at a high position, so that even if the both ends are broken, a large amount of leakage is not caused.

4. Because the heat pipe 3 used for normal heat removal of the reactor has high reliability, and the influence of the failure of part of the heat pipe 3 on the whole heat exchange is not great, the emergency waste heat removing device which can also be used in the accident situation is invented based on the heat pipe, the heat preservation flow channel 5 is additionally arranged on the heat pipe 3 outside the main container 1, the heat preservation flow channel is opened in the accident situation, and then the function of removing the waste heat of the reactor core can be executed in an air cooling mode.

5. According to the invention, natural circulation flow is formed in the reactor core through special arrangement of the fuel assembly, the heat pipe 3 and the components in the main container 1, and the heat exchange coefficient of the natural circulation flow is higher than that of the pool type heat exchange. The device is extremely simplified, the concept of a traditional fuel assembly, the concept of a main pump and the concept of a traditional main heat exchanger are not adopted, and an independent emergency waste heat discharging system is not adopted, so that the full passive operation, the normal operation and the accident operation can be realized.

It is to be understood that the above examples only represent preferred embodiments of the present invention, which are described in more detail and are not to be construed as limiting the scope of the invention; it should be noted that, for a person skilled in the art, the above technical features can be freely combined, and several variations and modifications can be made without departing from the scope of the invention; therefore, all changes and modifications that come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims (12)

1. A molten salt reactor based on heat pipe conduction, comprising: a main container (1), an annular cylinder (2), a heat pipe (3) and at least one graphite substrate (4);

a cavity (11) for flowing fuel molten salt fluid (14) is arranged in the main container (1);

the annular cylinder (2) is of a cylindrical structure with two open ends, is immersed in the fuel molten salt fluid (14) to define a first flow space (12) and a second flow space (13) by the chamber (11), the hot end of the heat pipe (3) is arranged in the first flow space (12), and the cold end of the heat pipe extends out of the main container (1) to lead out the heat of the reactor from the main container (1);

at least one graphite substrate (4) is arranged in the second flow space (13), a plurality of coolant flow channels (41) which are distributed at intervals are arranged in each graphite substrate (4), and the coolant flow channels (41) penetrate through the opposite two end surfaces of the graphite substrate (4) and are communicated with the first flow space (12);

the graphite matrix (4) acts as a moderator, nuclear reactions of nuclear fuel in the fuel molten salt fluid (14) in the second flow space (13) take place, thereby generating heat, the second flow space (13) acts as a heat source, and the first flow space (12) acts as a cold trap, so that the fuel molten salt fluid (14) forms a natural circulation flow between the first flow space (12) and the second flow space (13).

2. The molten salt reactor based on heat pipe conduction according to claim 1, wherein the heat pipe (3) comprises a plurality of heat pipe units (31) arranged at intervals apart, each of the heat pipe units (31) comprising an outer wall body (311), a wick (312) for flowing a liquid medium, and a steam flow channel (313) for flowing metal steam, which are arranged in sequence from outside to inside in the circumferential direction.

3. The molten salt reactor based on heat pipe conduction of claim 2, wherein each heat pipe unit (31) further comprises a heating evaporation section (314) immersed in the fuel molten salt fluid (14) and a heat dissipation condensation section (315) protruding out of the main vessel (1), and each heat pipe unit (31) has capillary force;

the liquid medium is vaporized in the heating evaporation section (314) by absorbing heat so as to form the metal vapor which flows in the vapor flow channel (313), the metal vapor is condensed in the heat dissipation condensation section (315) to form the liquid medium, and then the liquid medium flows back to the heating evaporation section (314) through the liquid suction core (312) to form a heat transfer circulation loop inside the heat pipe (3).

4. A molten salt reactor based on heat pipe conduction as claimed in claim 3 wherein the heat pipe unit (31) further comprises a heat pipe insulation section (316) provided between the heating evaporation section (314) and the heat dissipation condensation section (315).

5. The molten salt reactor based on heat pipe conduction of claim 4 further comprising a soak flow path (5) and a thermoelectric conversion system (6);

the heat preservation runner (5) is arranged outside the main container (1), the heat pipe unit (31) stretches out of the main container (1), enters the heat preservation runner (5) after passing through a heat pipe heat preservation section (316), and is connected with the thermoelectric conversion system (6) after passing through a heat pipe heat preservation section (316).

6. The molten salt reactor based on heat pipe conduction as claimed in claim 5, wherein the heat-preserving flow channel (5) is a closed chamber, all the heat pipe units (31) pass through the heat-preserving flow channel (5), an air inlet pipeline (51) and an air outlet pipeline (52) are connected to the heat-preserving flow channel (5), a first control valve (511) is arranged on the air inlet pipeline (51), and a second control valve (521) is arranged on the air outlet pipeline (52).

7. The molten salt reactor based on heat conduction of a heat pipe according to claim 6, wherein a heat preservation layer is arranged on the outer wall surface of the heat preservation runner (5), and the heat preservation layer is made of heat preservation materials.

8. The molten salt reactor based on heat conduction of a heat pipe as claimed in claim 1, further comprising a reflecting layer (7) attached to the inner wall surface of the annular cylinder (2) for reflecting neutrons into the core.

9. The molten salt reactor based on heat pipe conduction according to claim 8, characterized in that the annular cylinder (2) is a cylindrical structure made of carbon composite material or hastelloy.

10. A molten salt reactor based on heat pipe conduction according to claim 9, characterized in that a vacuum layer is provided in the wall of the annular cylinder (2) for avoiding heat transfer of the first flow space (12) and the second flow space (13) to enhance natural circulation.

11. The molten salt reactor of claim 1 further comprising a control rod assembly (8), the control rod assembly (8) comprising a reactivity control rod (81) and a shutdown rod (82);

a plurality of control pore canals (42) for inserting the reactivity control rods (81) and shutdown pore canals (43) for inserting the shutdown rods (82) are arranged in the graphite matrix (4).

12. The molten salt reactor of claim 1, wherein the fuel molten salt fluid (14) is capped with inert gas (16) at an upper portion.

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